LARGESTN Keep N largest coefficients
Usage: xo=largestn(x,N);
xo=largestn(x,N,mtype);
LARGESTN(x,N) returns an array of the same size as x keeping
the N largest coefficients.
LARGESTN takes the following flags at the end of the line of input
arguments:
'hard' Perform hard thresholding. This is the default.
'wiener' Perform empirical Wiener shrinkage. This is in between
soft and hard thresholding.
'soft' Perform soft thresholding.
'full' Returns the output as a full matrix. This is the default.
'sparse' Returns the output as a sparse matrix.
If the coefficients represents a signal expanded in an orthonormal
basis then this will be the best N-term approximation.
*Note:* If soft- or Wiener thresholding is selected, only N-1
coefficients will actually be returned. This is caused by the N*'th
coefficient being set to zero.
References:
S. Mallat. A wavelet tour of signal processing. Academic Press, San
Diego, CA, 1998.
Url: http://ltfat.github.io/doc/sigproc/largestn.html
See also: largestr.
Package: ltfat